The present invention relates to a portable optical code reader with a device for controlling the charge state of the reader battery.
Portable optical code, in particular bar code, readers are known, which comprise a small hand-held outer casing (e.g. of elongated tubular shape, tapering at one end) housing an electronic circuit and a rechargeable, e.g. Ni--Cd, battery for supplying the electronic circuit. The reader also comprises a light source, e.g. a LED, for illuminating an optical code, e.g. a bar code BC; and a light sensor cooperating with the electronic circuit and for receiving the radiation diffused by the code. The light sensor receives the radiation diffused by successive adjacent portions of the code as the reader is moved manually with respect to the code, and so generates a signal modulated by the succession of different-coloured code elements (i.e. light and dark bars in the case of a bar code). The alternating signal is then processed by the electronic circuit to extract the alphanumeric information associated with the optical code. More specifically, known readers feature a display device (e.g. a liquid-crystal display), which cooperates with the electronic circuit to display the alphanumeric information read in the code.
Known readers also cooperate with a battery charger for charging the reader battery, which is normally done by connecting a portion (e.g. an end portion) of the reader fitted with supply electrodes to electrodes on the battery charger to generate recharge current from the battery charger to the rechargeable battery, which is normally recharged when the reader is not in use. As the reader is normally carried by a user moving about in an industrial environment, often some distance from the battery charger, a close check must be kept on the actual charge state of the reader battery to prevent the battery from running down completely while the reader is in use, and to recharge the battery as it gets low.
Since monitoring the actual state of the battery charge involves drawing current from the battery, the frequency with which the charge must be monitored may result in rapid discharge of the battery.